A keystone is the wedge at the top of an arch upon which all the other components lean. Keystones are usually masonry in either cut stone, cast stone or brick. The key design feature is the last ...

When Medieval Europeans decided to build massive stone cathedrals, they had to use more complicated designs of arches: one with heavier supports on the sides (called flying buttresses, light blue in ...

Rachael Hood, Senior Editor The Stone Arch Bridge is a must-see for any architecture buff. This 2,100-foot granite and limestone bridge (featuring a total of 23 arches) was constructed in 1883 and ...

Keystone plants have the same function in nature as a keystone has in a Roman arch. Pull out the wedge-shaped stone, which locks all the other stones into place, and the arch either collapses or ...